T.M. No. 16 - November 1965 



A Lognorma I Size Distribution Model for Estimating Stability of 

 Beach Fill Materia I by W. C. Krumbein and W. R. James 



An analytical approach to the problem of estimating the "extra 

 amount" of beach fill needed when available borrow material is finer 

 than native sand composing the beach area is discussed. A mathemati- 

 cal solution is offered for those cases where borrow material is 

 less we I I -sorted than native beach material. If fill is better 

 sorted, there is no direct mathematical solution, and required fill 

 quantities must be based on past experience and empirical procedures. 

 Mathematical theory underlying the method of analysis is based on a 

 simple model assuming lognormalcy of particle size distribution. 

 A "critical ratio" of amount of borrow material needed to produce 

 the size distribution of the native sand is defined such that when 

 the ratio has a maximum, the oroblem can be solved. 



T.M. No. 17 - February 1966 



A Method for Calculating and Plotting Surface Wave Rays 

 by W. Stan ley Wi I son 



A method using a digital computer and incremental plotter for 

 calculating and plotting wave rays (orthogona 1 s) is described. Given 

 grid of depth values, initial position of wave ray, and direction of 

 travel and period of wave, successive points along ray path are cal- 

 culated. For each point on path, water depth and bottom slope are 

 estimated from depth grid by linear interpolation; wave speed and 

 curvature computed according to classic theory; and location of next 

 successive point approximated by iteration procedure. Numerical 

 results may be plotted automatically. Example of results, obtained 

 by application of method at Virginia Beach, Virginia, is presented. 

 Unless the bathymetry of area is unusually smooth, this method is 

 faster than manual construction. The computer program is included. 



T.M. No. 18 - November 1966 



Correlation of Littoral Transport with Wave Energy Along Shores 

 of New York and New Jersey by John C. Fa i rchi I d 



Shows the results of an office study which correlated field 

 measurements of net littoral transport with the average net along- 

 shore component of wave energy. Employs a survey attempt toward a 

 "wave energy- littoral transport" correlation for a 500-mile stretch 

 of coastline by.^applying wave refraction analysis to wave hindcasts 

 from synoptic weather charts. Littoral transport rates were obtained 

 from beach erosion control and other applicable reports of the study 

 area. Results are presented in tabular and graphical form and com- 

 pared to other "wave energy - I ittora I transport" relationships. The 

 conclusion is made that the correlation should be reliable within 

 the I imits of the data scatter. 



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